net: Add net tdb command to print information from tdb records

net: Add net tdb command to print information from tdb records

The main purpose is to debug "hot" records from ctdb. ctdb tracks
contended records and identifies them by key in the dbstatistics:

DB Statistics: locking.tdb
[...]
 Num Hot Keys:     1
     Count:3 Key:6a4128e3ced4681b02a00000000000000000000000000000

This command allows querying additional information for the associated
key to identify the affected file. For now this only adds a subcommand
for the locking.tdb, but could be extended to others:

net tdb locking 6a4128e3ced4681b02a00000000000000000000000000000
Share path:            /test/share
Name:                  testfile
Number of share modes: 2

Signed-off-by: Christof Schmitt <cs@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>